Re: [PATCH io_uring-next/net-next v2 0/4] implement io_uring notification (ubuf_info) stacking

[Pavel Begunkov <asml.silence@gmail.com>]

On 4/19/24 12:08, Pavel Begunkov wrote:
> Please, don't take directly, conflicts with io_uring.

When everyone is happy with the patches, Jens and Jakub will hopefully
help to merge them. E.g. first staging net/ specific changes [1] and then
handling all conflicts on the io_uring side.

[1] https://github.com/isilence/linux.git iou-sendzc/notif-stacking-v2-netonly


> To have per request buffer notifications each zerocopy io_uring send
> request allocates a new ubuf_info. However, as an skb can carry only
> one uarg, it may force the stack to create many small skbs hurting
> performance in many ways.
> 
> The patchset implements notification, i.e. an io_uring's ubuf_info
> extension, stacking. It attempts to link ubuf_info's into a list,
> allowing to have multiple of them per skb.
> 
> liburing/examples/send-zerocopy shows up 6 times performance improvement
> for TCP with 4KB bytes per send, and levels it with MSG_ZEROCOPY. Without
> the patchset it requires much larger sends to utilise all potential.
> 
> bytes  | before | after (Kqps)
> 1200   | 195    | 1023
> 4000   | 193    | 1386
> 8000   | 154    | 1058
> 
> The patches are on top of net-next + io_uring-next:
> 
> https://github.com/isilence/linux.git iou-sendzc/notif-stacking-v2
> 
> First two patches based on net-next:
> 
> https://github.com/isilence/linux.git iou-sendzc/notif-stacking-v2-netonly
> 
> v2: convert xen-netback to ubuf_info_ops (patch 1)
>      drop two separately merged io_uring patches
> 
> Pavel Begunkov (4):
>    net: extend ubuf_info callback to ops structure
>    net: add callback for setting a ubuf_info to skb
>    io_uring/notif: simplify io_notif_flush()
>    io_uring/notif: implement notification stacking
> 
>   drivers/net/tap.c                   |  2 +-
>   drivers/net/tun.c                   |  2 +-
>   drivers/net/xen-netback/common.h    |  5 +-
>   drivers/net/xen-netback/interface.c |  2 +-
>   drivers/net/xen-netback/netback.c   | 11 ++--
>   drivers/vhost/net.c                 |  8 ++-
>   include/linux/skbuff.h              | 21 +++++---
>   io_uring/notif.c                    | 83 +++++++++++++++++++++++++----
>   io_uring/notif.h                    | 12 ++---
>   net/core/skbuff.c                   | 36 ++++++++-----
>   10 files changed, 134 insertions(+), 48 deletions(-)
> 

-- 
Pavel Begunkov